[ARC5] 24vdc power

[Bob kb8tq]

Hi

Batteries self discharge simply sitting on the shelf. Most lead acid
spec sheets talk about this in terms or “percent per month” sort 
of numbers. If your 200AH battery discharges 1% a month, that’s
right at a milliamp. 

A modern silicon diode likely has leakage numbers in the nanoamp
range. A microamp would be pretty massive on a modern part. The
discharge from a couple diodes in a bridge is not going to have a
significant impact compared to a single isolation diode. 

All we’re talking about here is that added isolation diode. The rest
is very much “up to the user”. 

Bob

> On Sep 5, 2022, at 9:22 PM, Brian Clarke <brianclarke01 at optusnet.com.au> wrote:
> 
> Not a good idea, Bob.
>  
> Some batteries, particularly lead-acid, see the pulsing DC as charge-discharge cycles, shortening their lives. Diodes do not have infinite reverse resistance; so, leaving a battery connected to a transformer + rectifier combo will discharge the battery a bit faster than shelf life.
> If you don’t use a battery or regulator to smooth out the pulses, your outgoing radio signal will be modulated with 100 Hz or 120 Hz noise.
>  
> 73 de Brian, VK2GCE
>  
> From: Bob kb8tq [mailto:kb8tq at n1k.org] 
> Sent: Tuesday, 6 September 2022 1:54 PM
> To: Brian Clarke
> Cc: Glenn Little WB4UIV; ARC-5
> Subject: Re: [ARC5] 24vdc power
>  
> Hi
>  
> If this is a basic “no regulation” supply ( = transformer driving diodes into a load + 
> (maybe) a cap …) the addition of a diode to isolate this or that does nothing useful. 
>  
> Bob
>  

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